JP2013090443A - Permanent magnet motor and washing machine - Google Patents

Abstract

High torque can be generated while reducing the size, weight and cost.
A stator 7 in which a stator coil is wound around a stator core 9 and substantially rectangular block-like permanent magnets 14 and 15 constituting a plurality of magnetic poles having different polarities on the side corresponding to the stator core 9 of the frame are arranged. The permanent magnets 14 and 15 constituting the plurality of magnetic poles have a length direction located on the circumferential side of the stator core 9 and a width direction located on the radial side of the stator core 9. The permanent magnets 14 and 15 constituting the plurality of magnetic poles are made of a sintered powder of magnetic powder, and both end portions in the thickness direction are set so as to protrude from both end portions in the thickness direction of the stator core 9. The magnetic flux flows in the longitudinal direction on the anti-stator core side in the circumferential direction and flows in the radial direction on the stator core 9 side, and in the thickness direction side, the magnetic flux flows in the thickness direction on the anti-stator core side. Oriented flow radially stator core 9 side.
[Selection] Figure 1

Description

  The present embodiment relates to a permanent magnet motor including a plurality of permanent magnets as magnetic poles on a rotor and a washing machine including the permanent magnet motor.

  For example, in a drum-type washing machine, a permanent magnet motor is used as a motor that rotationally drives a drum as a washing machine load. When the rotor is of the outer rotor type that is located outside the periphery of the stator, the permanent magnet motor is formed into a flat, covered cylindrical container with a magnetic material such as an iron plate. The inner peripheral side portion is located outside the peripheral portion of the stator. A plurality of (many) permanent magnets are arranged on the entire circumference on the inner circumferential surface of the inner circumferential side portion which is the stator side of the frame. This permanent magnet is generally rectangular and is generally oriented so that the magnetic flux simply flows linearly in the width direction (the radial direction of the stator). In order to make a wave, there is a permanent magnet in which the stator side surface is formed in an arc shape with the center protruding toward the stator side. The frame is required to have a sufficient thickness as a back yoke that sufficiently circulates the magnetic flux flowing from one permanent magnet to the opposite stator side.

  However, when the magnetic force of the permanent magnet is large, the frame becomes too thick and difficult to process. Therefore, a ring is added as a back yoke to the peripheral side portion that is the anti-stator of the frame. While increasing the size, it is moderately retained, and the amount is compensated by a ring so that the magnetic flux is sufficiently recirculated.

  In this case, it is necessary to magnetically and mechanically bond the ring together with the permanent magnet to the frame, and for this reason, a synthetic resin mold layer is applied from each adjacent portion of the permanent magnet to the outer periphery of the ring, Permanent magnets and rings are fixed to the peripheral side of the frame.

  In the above, especially when the magnetic force of the permanent magnet is large, in order to sufficiently recirculate the magnetic flux flowing through the permanent magnet, the frame needs to have a relatively large thickness, and a ring is also required. A large volume of the mold layer is also required. As a result, the overall size is increased, the weight is increased, the inertia torque is increased, and the characteristics of the electric motor are deteriorated and folded, and the cost is increased.

Therefore, recently, a rotor is provided with a permanent magnet made of a sintered body of magnetic powder in which the flow of magnetic flux is oriented anisotropically, and a plurality of the permanent magnets are placed on the stator side of the frame made of magnetic material. Permanent magnet motors that are arranged alternately are considered. According to this, the flow of the magnetic flux of the permanent magnet is oriented in an anisotropic manner, and the magnetic poles that flow through one permanent magnet are transferred to adjacent permanent magnets because the polarities are alternately arranged. Most of it flows and is sufficiently refluxed, and the amount of reflux that flows through the frame is reduced. Therefore, the frame does not need a thickness as a back yoke, and a ring as a back yoke is not necessary. Furthermore, only a small volume of the synthetic resin mold layer is required. As a result, the overall size can be reduced, the weight thereof is reduced, and the cost is reduced.
Recently, however, the demand for permanent magnet motors has increased due to, for example, the spread of electric vehicles, and it is possible to generate a larger magnetic force (in other words, torque) as a permanent magnet while reducing the size, weight, and cost. It is desired to develop a permanent magnet motor that can be used.

JP 2003-299282 A

  Accordingly, a permanent magnet motor capable of generating high torque while achieving size reduction, weight reduction, and cost reduction, and a washing machine using the permanent magnet motor are provided.

  The permanent magnet motor of this embodiment includes a stator in which a stator coil is wound around a stator core, and a substantially rectangular block-shaped permanent magnet that forms a plurality of magnetic poles having different polarities on the side corresponding to the stator core of the frame. The permanent magnets constituting the plurality of magnetic poles are arranged such that the length direction is located on the circumferential side of the stator core and the width direction is located on the radial side of the stator core. And the permanent magnets constituting the plurality of magnetic poles are made of a sintered powder of magnetic powder, and both end portions in the thickness direction are set to have a thickness dimension protruding from both end portions in the thickness direction of the stator core. The magnetic flux flows in the circumferential direction on the anti-stator core side in the lengthwise direction and flows in the radial direction on the stator core side, and the magnetic flux is thick on the anti-stator core side in the thickness direction side. And wherein the oriented to flow in the flow stator core side radially direction.

  The washing machine of this embodiment is characterized in that the washing machine load is rotationally driven by the permanent magnet motor described above.

1 shows an embodiment, (a) is a partially enlarged sectional view of a stator and a rotor, and (b) is a magnetic characteristic diagram of a permanent magnet. Perspective view of permanent magnet motor Partial enlarged perspective view of stator and rotor (A) is a figure which shows the arrangement | positioning relationship of the thickness direction of a stator and the permanent magnet for N poles, (b) is a magnetic characteristic figure of the permanent magnet for N poles (A) is a figure which shows the arrangement | positioning relationship of the thickness direction of a stator and the permanent magnet for S poles, (b) is a magnetic characteristic figure of the permanent magnet for S poles 1 shows a schematic configuration of a drum type washing machine, (a) is a longitudinal side view, (b) is a longitudinal rear view.

(One embodiment)
Hereinafter, an embodiment applied to a drum type washing machine will be described with reference to the drawings.
First, in FIG. 6, the water tank 2 is arrange | positioned in the outer case 1 of the washing machine. The water tank 2 has a substantially cylindrical shape in which the rear surface portion 2a (the right end surface portion in FIG. 6A), which is one end, is closed, and is elastically supported by a damper mechanism (not shown) in a state where the axial direction is substantially horizontal. ing. In the water tank 2, the drum 3 which comprises a rotation tank is arrange | positioned rotatably. The drum 3 also has a substantially cylindrical shape in which the rear surface portion 3a (the right end surface portion in FIG. 6A), which is one end portion, is closed, and is disposed in a state where the axial direction is substantially horizontal. A number of holes (not shown) are formed in the peripheral wall of the drum 3. Although not shown, the front portion 1a of the outer box 1 is provided with a door for opening and closing the laundry entrance, and an opening is formed on the front side of the water tub 2 and the drum 3 so that the laundry can be washed. The drum 3 is taken in and out through the material entrance.

  A permanent magnet motor 4 (hereinafter simply referred to as the motor 4) for rotating the drum 3 is disposed on the back surface of the rear surface portion 2a of the water tank 2. In this case, the motor 4 is an outer rotor type brushless DC motor, and a shaft 6 connected to the rotor 5 is connected to the rear portion of the drum 3. Therefore, a direct drive system in which the drum 3 is directly rotated by the motor 4 is employed. The drum 3 corresponds to a washing machine load that is rotationally driven by the motor 4.

The motor 4 will be described with reference to FIGS.
The stator 7 of the motor 4 includes a stator core 9 having a large number of teeth portions 8 on the outer peripheral portion, a stator coil 10 wound around each teeth portion 8, and a synthetic resin mounting portion 11. And attached to the rear surface portion 2a of the water tank 2 in a fixed state via the attachment portion 11. The number of teeth portions 8 is, for example, 36.

  The rotor 5 has a shallow container-like frame 12 made of a magnetic material having an annular wall 12a on the outer peripheral portion, and a total of 48 permanent magnets arranged on the inner peripheral portion of the annular wall 12a. 14 and 15, and a synthetic resin mold layer 13 (see FIGS. 1 and 3) for fixing the permanent magnets 14 and 15 to the annular wall 2a. The shaft 6 is connected to the provided shaft mounting portion 16.

  The permanent magnet 14 is for the north pole where the stator 7 side (tooth portion 8 side of the stator core 9) is the north pole, and the permanent magnet 15 is for the south pole where the stator 7 side is the south pole. Are arranged as follows. The permanent magnets 14 and 15 are formed in a substantially rectangular block shape, and the circumferential direction of the frame 12 (stator core 9) is in the length direction and the radial direction is in the width direction. 4 and 5, the thickness dimension Lm of the permanent magnets 14 and 15 is set to be larger than the thickness dimension Ls of the stator core 9 of the stator 7, and both end portions in the thickness direction are stator cores. 9 protrudes from both end portions in the thickness direction. That is, the permanent magnets 14 and 15 are overlapped with the stator core 9. The surface of the permanent magnet 14 on the side corresponding to the stator core 9 of the stator 7 (the surface on the N pole side) is centered along the outer periphery of the stator 7 (stator core 9), as shown in FIG. It is formed in a concave arcuate shape to form an arcuate surface 14a, and corners at both ends in the length direction are cut away to form a notch 14b. Similarly, the surface of the permanent magnet 15 corresponding to the stator core 9 of the stator 7 (surface on the S pole side) is centered along the outer periphery of the stator 7 (stator core 9) as shown in FIG. Is formed into a concave arcuate shape to form an arcuate surface 15a, and corners at both ends in the length direction are cut away to form a notch 15b.

  The permanent magnets 14 and 15 constituting the plurality of magnetic poles are composed of neodymium magnets or ferrite magnets obtained by sintering magnetic powder, and the flow of the magnetic flux φ is that of the stator 7 on both the length direction side and the thickness direction side. It is oriented in an anisotropy concentrated in the center on the stator core 9 side. That is, as shown in FIG. 1A, on the length direction side of the permanent magnet 14 for N pole, the magnetic flux φ flows in the circumferential direction from both ends on the annular wall 12a side (anti-stator core 9 side), and on the stator 7 side ( The magnetic flux φ flows radially from the center of the stator 7 side (stator core 9 side) to the center of the stator core 9 side, and the annular wall 12a side ( Oriented so as to flow in the circumferential direction toward both ends of the anti-stator core 9 side. As a result, the magnetic flux distribution on the surface of the permanent magnets 14 and 15 on the side corresponding to the stator core 9 of the stator 7 is a sinusoidal shape as shown in FIG.

  On the thickness direction side of the N-pole permanent magnet 14, as shown in FIG. 4A, the magnetic flux φ is from both ends in the thickness direction on the annular wall 12 a (see FIG. 2) side (anti-stator core 9 side). Flowing in the thickness direction, flowing in the radial direction toward the center of the stator 7 on the stator core 9 side, and on the thickness direction side of the permanent magnet 15 for the S pole, as shown in FIG. It is oriented so that it flows radially from the center on the stator core 9 side and flows in the thickness direction to both ends in the thickness direction on the annular wall 12a (see FIG. 2) side (on the side opposite the stator core 9). As a result, the magnetic flux distributions on the surfaces of the permanent magnets 14 and 15 corresponding to the stator core 9 are both sinusoidal as shown in FIGS. 4B and 5B.

Then, the orientation and sintering of the permanent magnets 14 and 15 formed by sintering the magnetic powder is performed by, for example, putting the magnetic powder in a cavity in the mold together with water to be in a free state. The magnetic powder is pressed and hardened with discharge of water in the cavity while applying a magnetic field so that it flows as shown in FIG.
Although not shown, the motor 4 is controlled via an inverter circuit by a control device including a microcomputer. The control device has a function of controlling the washing operation described later.

The operation of the above configuration will be described.
When starting the washing operation, the control device first performs a water supply stroke. In the water supply stroke, a water supply valve (not shown) is opened and water is supplied into the water tank 2 and then into the drum 3 to be stored. Next, a washing process is performed. In the washing step, the drum 3 is rotated forward and backward by the motor 4 at a low rotational speed of, for example, 50 to 60 rpm while the detergent is put into the water tank 2. Thereby, the laundry accommodated in the drum 3 is washed. After performing a washing process for a predetermined time, a draining process is performed. During the drainage process, the drainage valve (not shown) connected to the discharge port of the water tank 2 is opened while the drum 3 is stopped, so that the water in the water tank 2 (in the drum 3) is discharged outside the machine. To do.

Next, a water supply stroke is performed again, and water is supplied into the water tank 2 and thus into the drum 3 to be stored. Next, a rinsing process is performed. In the rinsing process, the same control as in the washing process is performed except that no detergent is used. That is, the laundry in the drum 3 is rinsed by rotating the drum 3 forward and backward at a low rotational speed of, for example, 50 to 60 rpm by the motor 4. Thereafter, a drainage process similar to that described above is performed.
Next, a dehydration process is performed. In the dehydration process, the drum 3 is rotated in one direction by the motor 4 at a high speed of, for example, 1000 rpm. Thereby, the laundry in the drum 3 is centrifugally dehydrated. Thus, the washing operation ends.

  According to such an embodiment, the thickness dimension Lm of the permanent magnets 14 and 15 is set larger than the thickness dimension Ls of the stator core 9 of the stator 7, and both end portions in the thickness direction of the stator core 9. The permanent magnets 14 and 15 project from the both ends in the thickness direction, and the permanent magnets 14 and 15 are arranged in the center on the stator 7 side (stator core 9 side) in both the length direction side and the thickness direction side. Since the magnetic flux distribution acting on the teeth portion 8 of the stator 7 becomes a sine wave shape and a stronger magnetic force acts, the high torque can be generated. It is suitable as a motor 4 that performs a washing and rinsing process requiring low speed and high torque.

  In addition, since the permanent magnets 14 and 15 are arranged with alternately different polarities, most of the magnetic flux φ flowing through one permanent magnet flows into the adjacent permanent magnets and is sufficiently returned to the frame 12. The amount of reflux through the flow is reduced. Therefore, the frame 12 does not need a thickness as a back yoke, and a ring as a back yoke is not necessary. Furthermore, only a small volume of the synthetic resin mold layer 13 is required. As a result, the motor 4 can generate a high torque while being reduced in size, weight, and cost.

  Further, since the surfaces of the permanent magnets 14 and 15 corresponding to the stator core 9 of the stator 7 are formed on the arc surfaces 14a and 15a along the stator core 9, the air gap between the stator 7 and the stator 7 can be minimized, The volume of the rotor 5 can be minimized while effectively applying a magnetic force to the stator coil 10. Since the surfaces corresponding to the stator core 9 of the permanent magnets 14 and 15 are formed on the circular arc surfaces 14a and 15a, the air resistance of the rotation of the rotor 5 is small, and the generation of noise due to turbulence can be prevented. Furthermore, since the corners at both ends of the arcuate surfaces 14a and 15a of the permanent magnets 14 and 15 are cut away to form the notches 14b and 15b, the change in magnetic characteristics due to the demagnetizing action at the corners. Can be prevented.

(Other embodiments)
The motor 4 is not limited to the outer rotor type, and may be an inner rotor type.
The washing machine can be applied to a washing / drying machine having a drying function.
The washing machine is not limited to a drum-type washing machine, and can be applied to a vertical washing machine having a rotating tub in the vertical direction. In this type of washing machine, the permanent magnet motor rotates the stirrer that stirs the laundry in the washing process and the rinsing process at a low speed in the forward and reverse directions. Let In this case, the washing machine load driven by the permanent magnet motor is a stirring body and a rotating tub.

  As described above, according to the present embodiment, a substantially rectangular block-shaped permanent magnet comprising a stator formed by winding a stator coil around a stator core and a plurality of magnetic poles having different polarities on the side corresponding to the stator core of the frame. The permanent magnets constituting the plurality of magnetic poles are positioned on the circumferential direction side of the stator core and the width direction is positioned on the radial side of the stator core. The permanent magnets that are disposed in this manner and that have both end portions in the thickness direction projecting from both end portions in the thickness direction of the stator core and that constitute the plurality of magnetic poles are sintered with magnetic powder. The magnetic flux flows in the circumferential direction on the anti-stator core side in the longitudinal direction and flows in the radial direction on the stator core side, and the magnetic flux increases in the thickness direction on the anti-stator core side. And wherein the oriented to flow in the radial direction in the direction the flow stator core side. With such a configuration, a high torque can be generated as a permanent magnet motor while achieving a reduction in size, weight, and cost.

  Although several embodiments have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 1 is an outer case, 3 is a drum (washing machine load), 4 is a permanent magnet motor, 5 is a rotor, 7 is a stator, 8 is a teeth portion, 9 is a stator core, 10 is a stator coil, 13 is a mold layer, Reference numeral 14 denotes an N pole permanent magnet, and 15 denotes an S pole permanent magnet.

Claims (4)

A permanent comprising a stator formed by winding a stator coil around a stator core, and a rotor in which substantially rectangular block-shaped permanent magnets constituting a plurality of magnetic poles having different polarities are arranged on the side of the frame corresponding to the stator core. In magnet motor,
The permanent magnets constituting the plurality of magnetic poles are disposed such that the length direction is positioned on the circumferential direction side of the stator core and the width direction is positioned on the radial direction side of the stator core, and the permanent magnets are arranged in the thickness direction. Both end portions are set to thickness dimensions protruding from both end portions in the thickness direction of the stator core,
The permanent magnets constituting the plurality of magnetic poles are made of a sintered body of magnetic powder, and the magnetic flux flows in the circumferential direction on the anti-stator core side in the length direction side and flows in the radial direction on the stator core side, and on the thickness direction side. A permanent magnet motor characterized in that the magnetic flux is oriented so as to flow in the thickness direction on the anti-stator core side and in the radial direction on the stator core side.   The permanent magnet motor according to claim 1, wherein the surface of the permanent magnet on the stator core side is formed in an arc shape along the stator core.   3. The permanent magnet motor according to claim 1, wherein corner portions of both end portions in the length direction on the side corresponding to the stator core of the permanent magnet are cut off.   A washing machine, wherein the washing machine load is rotationally driven by the permanent magnet motor according to any one of claims 1 to 3.

Images